There are many applications, in mining and in other industries, in which continuous belt conveyors move bulk materials such as coal, grain, and the like from one location to another. In any such system the bulk material is deposited on the moving conveyor belt; interruption of belt movement to receive a new input is not economically feasible.
One major problem in the input station of any continuous conveyor belt system is leakage of the bulk material. Broadly speaking, this has been met to a substantial extent by resilient aprons affixed to lower edges of rigid skirtboards at the input station. Examples of previously known resilient skirtboard aprons and their mounts are disclosed in Gordon U.S. Pat. No. 4,231,471, U.S. Pat. No. 4,436,446, U.S. Pat. No. 4,877,125, and U.S. Pat. No. 4,989,727. Perhaps the best such skirtboard apron is the simple but effective device described and claimed in Gordon U.S. Pat. No. 4,989,727, sold commercially by Arch Environmental Equipment, Inc. of Paducah, Ky. under the Trademark ATLASTASEAL.RTM.. Even that skirtboard apron, however, may have leakage problems, particularly if there is appreciable movement of the conveyor belt, vertically or laterally, through the input station.
It has been conventional, in the input stations for continuous belt conveyors, to support the conveyor belt in a generally open upwardly-facing U-shaped configuration through the input station on three separate series of support rollers. This input station configuration has one set of central horizontal support rollers for the center of the belt. On each side there is another set of support rollers projecting upwardly at an acute angle and supporting a side portion of the belt.
Inevitably, there is some sagging of the belt between each set of support rollers, with resulting leakage problems. This kind of leakage has been reduced in some instances by modifying the input station to afford a plurality of elongated stationary support rails the conveyor belt; the outer side portions of the belt are supported at an acute angle to the center portion of the belt. However, the benefit of the resulting reduction in leakage is partially offset by increased drag on the conveyor belt. A further improved conveyor belt input station provided by the kit disclosed in Archer U.S. Pat. No. 5,350,053. But that conveyor belt input station is not always entirely satisfactory, particularly for heavily loaded conveyor belts having a width of four feet (120 cm) or more.